HP 54520 Series Service Manual page 132

Main Assembly Theory
Family Acquisition Differences The following explains the differences in the three
models that comprise the rest of this family, the HP 54540A, 54522A, and 54520A.
e The HP 54540A oscilloscope has four channels like the HP 54542A except that its sample
rate capability is 500 MSa/s with four channels running and 1 GSa/s with two channels
running. The acquisition architecture is identical to the HP 54542A.
The HP 54522A has the sample rate capability of the HP 54542A, 2 GSa/s, but only two
signal channels. The third channel position is unused and the fourth channel position is
used for an External Trigger. The external trigger uses an attenuator/preamp for signal
conditioning and has some of the ranging capability of a channel but no acquisition circuitry
(there is no ADC hybrid). The output of the external trigger attenuator/preamp is fed to
the analog trigger just like a channel.
The HP 54520A has the two-channel configuration of the HP 54522A with 500 MSa/s
sample rate capability on both channels.
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